Embodiments of the present disclosure generally relate to methods and devices for controlling rate adaptive pacing.
Clinical studies related to cardiac pacing have shown that a select (e.g., optimal) atrio-ventricular pacing delay (AV delay) can improve cardiac performance. However, the select AV delay depends on a variety of factors that may vary over time. For example, what is “optimal” may vary over time. An optimization of AV/PV pacing delay may occur at implantation and sometimes, re-optimization may occur during a follow-up consultation. While such optimizations are beneficial, the benefits may not be long lasting due to changes In various factors related to device and/or cardiac function.
Various systems and methods are provided for allowing an implantable medical device (IMD) to determine and/or adjust atrio-ventricular (AV/PV) delays and/or interventricular (VV) pacing delays so as to help maintain the pacing delays at select values. In particular, techniques have been set forth for exploiting various interventricular conduction delays to determine optimal AV/PV/VV pacing delays. Techniques have also been set forth for exploiting the VV delays to determine which ventricles should be paced—the left ventricle (LV), the right ventricle (RV), both ventricles, or neither.
Other techniques have been set forth for determining AV/PV delays based on inter-atrial conduction intervals and interventricular conduction intervals. In particular, see U.S. Pat. No. 7,248,925, to Bruhns et al., entitled “System and Method for Determining Optimal Atrioventricular Delay based on Intrinsic Conduction Delays,” which is fully incorporated by reference herein.
More recently, systems have been proposed to provide rate adaptive adjustment of the PR and AR delays using sensed and paced atrial signals durations, activity responsive optimal PV/AV and VV delays etc. However, an opportunity remains to continue to improve mechanisms for adjusting rate adaptive therapies.